Scanner Light Source Timing Control for Document Detection
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Solution Overview
Problem
Existing image scanning devices face issues with user comfort due to light exposure from the light source, which can cause discomfort and potential eye damage, and increased production costs from using high-performance document detection sensors to mitigate these issues.
Innovation Solution
An image scanning device with a control unit that introduces a lighting delay period after detecting the closure of the document pressing unit, allowing the light source to be turned on at a safe angle to reduce light exposure to the user and avoid mistaken detection of the pressing unit as a document, thereby minimizing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the document detection sensor detects closing of the document pressing unit when the pressing unit is close to the contact glass, then the document size can be detected, but the document pressing unit may be mistakenly detected as a document
Solution Approach 1:
The light source is turned on in advance before the document pressing unit closes completely, allowing the document size to be detected while the pressing unit is still at an angle where it cannot be mistaken for a document. This preliminary action prevents detection errors by ensuring the sensor only measures actual documents, not the pressing unit itself.
2Measurement precision
If the light source is turned on while the document pressing unit is at a large angle to enable document size detection, then document size can be measured, but light from the light source may enter the eyes of the user causing discomfort or damage
Solution Approach 1:
The light source is activated preliminarily when the document pressing unit is still at a large angle during the closing process, enabling document size detection to occur before the pressing unit reaches positions where light would directly enter user eyes. This timing strategy accomplishes both measurement and safety goals.
Solution Approach 2:
The system uses the natural closing motion of the document pressing unit itself to control light source activation timing. The pressing unit's own movement serves as the trigger mechanism, eliminating the need for separate sensors or complex control systems while achieving safe and accurate operation.
3Measurement precision
If a high-performance document detection sensor is used to solve the detection accuracy and reliability problems, then detection precision improves, but production costs increase
Solution Approach 1:
The system changes the temporal parameter of light source activation rather than upgrading hardware. By adjusting when the light turns on based on the pressing unit's position, the existing simple sensor achieves accurate document detection without misidentifying the pressing unit, avoiding the need for expensive high-performance sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces light exposure to the user and prevents mistaken document detection without the need for high-performance sensors, maintaining user comfort and controlling production costs.
Implementation Method 1
a scanning unit including a light source for illuminating the document and configured to optically scan the document; a photoelectric conversion element
Data Source
AI summary
A disclosed image scanning device includes a document table; a document pressing unit configured to press a document placed on the document table; a scanning unit including a light source for illuminating the document and configured to optically scan the document; a photoelectric conversion element; an open/close detection unit configured to detect opening and closing of the document pressing unit; and a control unit configured to turn on the light source of the scanning unit and thereby to cause the photoelectric conversion element to detect a size of the document if the closing of the document pressing unit is detected by the open/close detection unit or if a scanning start signal is detected. The control unit is configured to turn on the light source after a lighting delay period from a time when the closing of the document pressing unit is detected. The lighting delay period is changeable.